TenneT is a regulated transmission system operator with very large capital expenditure needs, rapidly rising debt, and negative earnings in 2022. This creates a strong strategic rationale to use hybrid capital: it can support credit metrics because rating agencies may give partial equity credit, while being cheaper and less dilutive than common equity.

Key points from the facts:

- Hybrid capital outstanding at 2023-01-01: EUR 2.125bn.
- Equity at 2023-01-01: EUR 7.713bn.
- Borrowings at 2023-01-01: long-term EUR 19.006bn + short-term EUR 0.709bn = EUR 19.715bn.
- Approximate debt plus equity capital: EUR 19.715bn + EUR 7.713bn = EUR 27.428bn.
- S&P cap on equity credit: 15% of total adjusted capital.
- 15% cap based on this approximate capital base: 0.15 × EUR 27.428bn ≈ EUR 4.114bn.
- Existing hybrid capital as a percentage of the cap: EUR 2.125bn / EUR 4.114bn ≈ 52%.

So TenneT is already using roughly half of the S&P hybrid equity-credit capacity.

The market environment in 2022 was less attractive than in 2020–2021 because swap rates rose sharply and corporate credit yields/spreads increased. Hybrid issuance would therefore be considerably more expensive than in prior years. However, TenneT’s large investment programme, weak reported profitability, and sharp increase in borrowings mean that maintaining some hybrid buffer is still useful. Fully maximizing the cap would likely be too aggressive given higher hybrid coupons and reliance on debt-like instruments, but underusing the capacity would not fit the company’s financing needs.

Among the choices, the closest and most balanced answer is 50% utilization of the S&P cap.

<answer>50%</answer>